spmt_os2.c revision f44d73842e45390adaecf468eb99d6654e29c33d
* 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * 3. The end-user documentation included with the redistribution, * if any, must include the following acknowledgment: * "This product includes software developed by the * Alternately, this acknowledgment may appear in the software itself, * if and wherever such third-party acknowledgments normally appear. * 4. The names "Apache" and "Apache Software Foundation" must * not be used to endorse or promote products derived from this * software without prior written permission. For written * permission, please contact apache@apache.org. * 5. Products derived from this software may not be called "Apache", * nor may "Apache" appear in their name, without prior written * permission of the Apache Software Foundation. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * ==================================================================== * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * Portions of this software are based upon public domain software * originally written at the National Center for Supercomputing Applications, * University of Illinois, Urbana-Champaign. * The max child slot ever assigned, preserved across restarts. Necessary * to deal with MaxClients changes across SIGUSR1 restarts. We use this * value to optimize routines that have to scan the entire scoreboard. /* *Non*-shared http_main globals... */ /* one_process --- debugging mode variable; can be set from the command line * with the -X flag. If set, this gets you the child_main loop running * in the process which originally started up (no detach, no make_child), * which is a pretty nice debugging environment. (You'll get a SIGHUP * early in standalone_main; just continue through. This is the server * trying to kill off any child processes which it might have lying * around --- Apache doesn't keep track of their pids, it just sends * SIGHUP to the process group, ignoring it in the root process. * Continue through and you'll be fine.). /* a clean exit from a child with proper cleanup */ * Done by each child at it's birth * Must be safe to call this on a restart. "Error creating accept lock. Exiting!");
"Error getting accept lock. Exiting!");
"Error freeing accept lock. Exiting!");
/* On some architectures it's safe to do unserialized accept()s in the single * Listen case. But it's never safe to do it in the case where there's * multiple Listen statements. Define SINGLE_LISTEN_UNSERIALIZED_ACCEPT * when it's safe in the single Listen case. /* Finally, this routine is used by the caretaker thread to wait for /* number of calls to wait_or_timeout between writable probes */ /* handle all varieties of core dumping signals */ /* At this point we've got sig blocked, because we're still inside * the signal handler. When we leave the signal handler it will * be unblocked, and we'll take the signal... and coredump or whatever * is appropriate for this particular Unix. In addition the parent * will see the real signal we received -- whereas if we called * abort() here, the parent would only see SIGABRT. /***************************************************************** * Connection structures and accounting... /* volatile just in case */ /* Um, is this _probably_ not an error, if the user has * tried to do a shutdown twice quickly, so we won't * worry about reporting it. /* Probably not an error - don't bother reporting it */ /* we want to ignore HUPs and USR1 while we're busy processing one */ /***************************************************************** * Child process main loop. /* Disable the restart signal handlers and enable the just_die stuff. * Note that since restart() just notes that a restart has been * requested there's no race condition here. set_signals();
/* signals aren't inherrited by child threads */ /* Get a sub pool for global allocations in this child, so that * we can have cleanups occur when the child exits. /* needs to be done before we switch UIDs so we have permissions */ /* Prepare to receive a SIGUSR1 due to graceful restart so that * (Re)initialize this child to a pre-connection state. * Wait for an acceptable connection to arrive. /* Lock around "accept", if necessary */ /* more than one socket */ /* Single Unix documents select as returning errnos * EBADF, EINTR, and EINVAL... and in none of those * cases does it make sense to continue. In fact * on Linux 2.0.x we seem to end up with EFAULT * occasionally, and we'd loop forever due to it. /* we remember the last_lr we searched last time around so that we don't end up starving any particular listening socket */ /* only one socket, just pretend we did the other stuff */ /* if we accept() something we don't want to die, so we have to break;
/* We have a socket ready for reading */ /* Our old behaviour here was to continue after accept() * errors. But this leads us into lots of troubles * because most of the errors are quite fatal. For * example, EMFILE can be caused by slow descriptor * leaks (say in a 3rd party module, or libc). It's * foolish for us to continue after an EMFILE. We also * seem to tickle kernel bugs on some platforms which * lead to never-ending loops here. So it seems best * to just exit in most cases. /* Linux generates most of these, other tcp * stacks (i.e. bsd) tend to hide them behind * getsockopt() interfaces. They occur when * the net goes sour or the client disconnects * after the three-way handshake has been done * in the kernel but before userland has picked /* We only get hit by an EINTR if the parent is "accept: (client socket)");
/* We've got a socket, let's at least process one request off the * socket before we accept a graceful restart request. We set * the signal to ignore because we don't want to disturb any * We now have a connection, so set it up with the appropriate * socket options, file descriptors, and read/write buffers. /* _beginthread didn't succeed. Fix the scoreboard or else * it will say SERVER_STARTING forever and ever /* In case system resources are maxxed out, we don't want Apache running away with the CPU trying to _beginthread over and /* start up a bunch of children */ * idle_spawn_rate is the number of children that will be spawned on the * next maintenance cycle if there aren't enough idle servers. It is * doubled up to MAX_SPAWN_RATE, and reset only when a cycle goes by * without the need to spawn. /* initialize the free_list */ /* try to keep children numbers as low as possible */ /* We consider a starting server as idle because we started it * at least a cycle ago, and if it still hasn't finished starting * then we're just going to swamp things worse by forking more. * So we hopefully won't need to fork more if we count it. * This depends on the ordering of SERVER_READY and SERVER_STARTING. /* always kill the highest numbered child if we have to... * no really well thought out reason ... other than observing * the server behaviour under linux where lower numbered children * tend to service more hits (and hence are more likely to have * their data in cpu caches). /* kill off one child... we use SIGUSR1 because that'll cause it to * shut down gracefully, in case it happened to pick up a request /* terminate the free list */ /* only report this condition once */ "server reached MaxClients setting, consider" " raising the MaxClients setting");
"server seems busy, (you may need " "spawning %d children, there are %d idle, and " /* the next time around we want to spawn twice as many if this * wasn't good enough, but not if we've just done a graceful /***************************************************************** "no listening sockets available, shutting down");
"Error allocating thread local storage" /* If we're doing a graceful_restart then we're going to see a lot * of children exiting immediately when we get into the main loop * below (because we just sent them SIGUSR1). This happens pretty * rapidly... and for each one that exits we'll start a new one until * we reach at least daemons_min_free. But we may be permitted to * start more than that, so we'll just keep track of how many we're * supposed to start up without the 1 second penalty between each fork. /* give the system some time to recover before kicking into "%s configured -- resuming normal operations",
/* XXX: if it takes longer than 1 second for all our children * to start up and get into IDLE state then we may spawn an /* non-fatal death... note that it's gone in the scoreboard. */ /* we're still doing a 1-for-1 replacement of dead * children with new children /* TODO: this won't work, we waited on a thread not a process else if (reap_other_child(pid, status) == 0) { /* Great, we've probably just lost a slot in the * scoreboard. Somehow we don't know about this "long lost child came home! (tid %d)",
tid);
/* Don't perform idle maintenance when a child dies, * only do it when there's a timeout. Remember only a * finite number of children can die, and it's pretty * pathological for a lot to die suddenly. /* we hit a 1 second timeout in which none of the previous * generation of children needed to be reaped... so assume * they're all done, and pick up the slack if any is left. /* In any event we really shouldn't do the code below because * few of the servers we just started are in the IDLE state * yet, so we'd mistakenly create an extra server. /* Time to gracefully shut down */ /* Kill off running threads */ "error %lu waiting for thread to terminate",
rc);
"error %lu killing thread",
rc);
/* cleanup pid file on normal shutdown */ "removed PID file %s (pid=%ld)",
"caught SIGTERM, shutting down");
/* we've been told to restart */ /* not worth thinking about */ /* advance to the next generation */ /* XXX: we really need to make sure this new generation number isn't in * use by any of the children. "SIGUSR1 received. Doing graceful restart");
/* kill off the idle ones */ /* This is mostly for debugging... so that we know what is still * gracefully dealing with existing request. But we can't really * do it if we're in a SCOREBOARD_FILE because it'll cause "SIGHUP received. Attempting to restart");
return "PidFile directive not allowed in <VirtualHost>";
"WARNING: detected MinSpareServers set to non-positive.");
"Resetting to 1 to avoid almost certain Apache failure.");
"Please read the documentation.");
"WARNING: MaxClients of %d exceeds compile time limit " " lowering MaxClients to %d. To increase, please " " HARD_THREAD_LIMIT define in %s.",
"WARNING: Require MaxClients > 0, setting to 1");
" does not exist or is not a directory",
NULL);
/* Stub functions until this MPM supports the connection status API */ "A file for logging the server process ID"),
"Number of child processes launched at server startup" ),
"Minimum number of idle children, to handle request spikes" ),
"Maximum number of idle children" ),
"Maximum number of children alive at the same time" ),
"Maximum number of requests a particular child serves before dying." ),
"The location of the directory Apache changes to before dumping core" ),
NULL,
/* hook to run before apache parses args */ NULL,
/* create per-directory config structure */ NULL,
/* merge per-directory config structures */ NULL,
/* create per-server config structure */ NULL,
/* merge per-server config structures */